<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
</head>
<body>
<canvas id="c" width="500" height="400 "></canvas>
<script>
  var ctx = c.getContext('2d')
  var i = new Image();
  i.src="default.png";
  i.onload = function(){
  }
  ctx.beginPath();
  ctx.arc(250,200,100,0, 2*Math.PI/180);
  ctx.stroke();
</script>
</body>
</html>